To compose in modern flamenco there are many traditional rules to follow according to the code itself.
There are two kinds:
1) Flamenco “por derecho”. Here is a video explaining it:
2) An approach we can say a bit “classical” in which specific settings are not flexible but fix beforehand.
That entails if there is an intro or not, how many falsetas are to be played, how many lyrics or “letras” are to be played between falsetas etc.
I would like to point out that the whole concept of an Intro Ad Libitum did not exist before Paco de Lucia as you can see from the following video lesson:
Then as an example of an arrangement I did on Paco de Lucia’s piece “Rio de la miel”. I choose the specific spots in which the falsetas and the lyrics or “letras” would combine together to sound well, in my opinion that buleria should be like this:
The order in which the falsetas are played does not matter as I demonstrated here:
The code of flamenco is divided into rhythmical aspects as well as melodical and aesthetical ones.
I suggest you listen to the following videos on the subject
It’s necessary to be acquainted with the following 8 aspects:
1)What is a “llamada” and a “Cierre”
2)What a falseta is http://www.cfgstudio.com/cfgs-grant17.html
3)How to ornament the lyrics or “letras” to make the singer and the rest of the band sound well http://www.cfgstudio.com/cfgs-grant25.html
4)To play in context (it applies to all the “palos” or styles but here is an example of that in Buleria)
5)Regard the rhythm structure of the piece *4 videos http://www.rdiaz.org/rdvideo683.html
6)If you play with others is important to know how to command them
7)If your composition is rather a modern one its important to be conversant with harmonic issues like the ones explained herein
8)To play along with a singer here are 3 golden rules
You can take a look to this nine video lessons for aspiring composers as an example http://www.rdiaz.org/rdvideo838.html
here you can see a composition without singer
and this is a composition with singer and similar instruments
In conclusion to sound flamenco for me is to be able to express my personal voice which I have discovered through Paco de Lucia’s style and music, and and here is an example of what I compose in that spirit http://www.rdiaz.org/rdvideo888.html
I hope to inspire you with my answer!